The invention relates to a V-belt pulley comprising an outer rim provided with at least one outwardly facing V-belt groove formed by turning in whose bottom a plurality of radially through-going openings are circumferentially interspaced and extend to the radially inwardly facing surface of the rim.
Such a V-belt pulley is known from GB patent nr. 865 797, in which the radial openings are formed by radial cutting through the rim of the V-belt pulley.
The object of the invention is to provide a V-belt pulley of the above type which can be made in a simple and rational manner.
The V-belt pulley according to the invention is characterised in that the pulley is cast with a rim having a radially inwardly facing surface provided with a plurality of circumferentially interspaced recesses of such a radial depth that the bottom thereof is arranged radially outside of the bottom of the V-belt groove such that the radially through-going openings are made by the turning thereof.
By forming the V-belt pulley with said recesses in its rim, the openings are automatically produced by turning of the V-belt groove. The cutting process of the V-belt pulley may thus be carried out in a manner corresponding to a conventional V-belt pulley without radial openings, whereby separate machining thereof is avoided. Consequently V-belt pulleys with openings which act to cool the pulley and V-belt and thus prolongs the life of the latter can be made essentially without increased production costs. Tests have shown that by using the V-belt pulley according to the invention the belt temperature is decreased by 10-15xc2x0 C. in relation to the use of conventional V-belt pulleys without radial openings in the bottom of the groove.
According to the invention, when seen in axial direction the radial recesses may have a groove-like form and thus be cast without using separate cores.
Furthermore according to the invention the recesses may be axially through-going from one side of the pulley to the other.
Moreover according to the invention the openings may be substantially evenly interspaced when seen in circumferential direction.
According to the invention, the radial openings may be of a length substantially corresponding to their interspacing when seen in circumferential direction.
Furthermore according to the invention the length of the openings may be 7-30 mm, preferably 15-25 mm when seen in circumferential direction.
Moreover according to the invention the depth of the recesses is such that the radial outer portion of the openings made by the turning of the groove is arranged radially inside of the V-belt received in the groove, whereby the V-belt does not engage the portion of the V-belt groove, in which the openings are formed.
Finally according to the invention the V-belt pulley may be made of SG iron.